Effects of Coffee and Caffeine Anhydrous Intake During Creatine Loading.
Study Goal
The researchers aimed to determine whether combining caffeine anhydrous or coffee with creatine loading enhances upper-body and lower-body strength and sprint performance compared to creatine alone or placebo.
Results Summary
The study found no significant performance benefits from combining caffeine (either as anhydrous or in coffee) with creatine compared to placebo. Mild gastrointestinal discomfort was reported in four subjects with creatine + caffeine, but no other side effects were noted.
Population
Physically active males (n = 54; age = 20.1 ± 2.1 years; weight = 78.8 ± 8.8 kg).
Effective Dosage
300 mg/day of caffeine anhydrous or 8.9 g/day of coffee (yielding 303 mg of caffeine).
Duration
5 days.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
creatine (CRE) loading | increase | strength measures | physically active males | - | were improved | #1 |
creatine (CRE) loading | no change | strength measures | physically active males | - | no significant time × treatment interactions | #2 |
creatine (CRE) loading | no change | peak power (PP) | physically active males | - | No significant interaction or main effects were observed | #3 |
creatine (CRE) loading | no change | total power (TP) | physically active males | - | no significant interactions among treatment groups | #4 |
creatine (CRE) loading | increase | serum creatinine (CRN) values | physically active males | - | showed increases | #5 |
creatine (CRE) loading in combination with caffeine anhydrous (CAF) | increase | strength measures | physically active males | - | were improved | #6 |
creatine (CRE) loading in combination with caffeine anhydrous (CAF) | no change | strength measures | physically active males | - | no significant time × treatment interactions | #7 |
creatine (CRE) loading in combination with caffeine anhydrous (CAF) | no change | peak power (PP) | physically active males | - | No significant interaction or main effects were observed | #8 |
creatine (CRE) loading in combination with caffeine anhydrous (CAF) | no change | total power (TP) | physically active males | - | no significant interactions among treatment groups | #9 |
creatine (CRE) loading in combination with caffeine anhydrous (CAF) | increase | serum creatinine (CRN) values | physically active males | - | showed increases | #10 |
creatine (CRE) loading in combination with caffeine anhydrous (CAF) | increase | gastrointestinal discomfort | four subjects | - | reported mild gastrointestinal discomfort | #11 |
creatine (CRE) loading in combination with coffee (COF) | increase | strength measures | physically active males | - | were improved | #12 |
creatine (CRE) loading in combination with coffee (COF) | no change | strength measures | physically active males | - | no significant time × treatment interactions | #13 |
creatine (CRE) loading in combination with coffee (COF) | no change | peak power (PP) | physically active males | - | No significant interaction or main effects were observed | #14 |
creatine (CRE) loading in combination with coffee (COF) | no change | total power (TP) | physically active males | - | no significant interactions among treatment groups | #15 |
creatine (CRE) loading in combination with coffee (COF) | increase | serum creatinine (CRN) values | physically active males | - | showed increases | #16 |
placebo (PLA) | increase | strength measures | physically active males | - | were improved | #17 |
placebo (PLA) | no change | strength measures | physically active males | - | no significant time × treatment interactions | #18 |
placebo (PLA) | no change | peak power (PP) | physically active males | - | No significant interaction or main effects were observed | #19 |
placebo (PLA) | no change | total power (TP) | physically active males | - | no significant interactions among treatment groups | #20 |
placebo (PLA) | no change | serum creatinine (CRN) values | physically active males | - | did not show increases | #21 |
The purpose of this study was to determine the effect of 5 days of creatine (CRE) loading alone or in combination with caffeine anhydrous (CAF) or coffee (COF) on upper-body and lower-body strength and sprint performance. Physically active males (n = 54; mean ± SD; age = 20.1 ± 2.1 years; weight = 78.8 ± 8.8 kg) completed baseline testing, consisting of 1 repetition maximum (1RM) and repetitions to fatigue with 80% 1RM for bench press and leg press, followed by a repeated sprint test of five, 10-second sprints separated by 60-second rest on a cycle ergometer to determine peak power (PP) and total power (TP). At least 72 hours later, subjects were randomly assigned to supplement with CRE (5 g of CRE monohydrate, 4 times per day; n = 14), CRE + CAF (CRE +300 mg·d of CAF; n = 13), CRE + COF (CRE +8.9 g of COF, yielding 303 mg of CAF; n = 13), or placebo (PLA; n = 14) for 5 days. Serum creatinine (CRN) was measured before and after supplementation, and on day 6, participants repeated pretesting procedures. Strength measures were improved in all groups (p ≤ 0.05), with no significant time × treatment interactions. No significant interaction or main effects were observed for PP. For TP, a time × sprint interaction was observed (p ≤ 0.05), with no significant interactions among treatment groups. A time × treatment interaction was observed for serum CRN values (p ≤ 0.05) that showed increases in all groups except PLA. Four subjects reported mild gastrointestinal discomfort with CRE + CAF, with no side effects reported in other groups. These findings suggest that neither CRE alone nor in combination with CAF or COF significantly affected performance compared with PLA.